Various heat dissipation concepts for cooling power components mounted using surface mount technology (SMT) are known. The heat can be dissipated by heat sinks which are disposed either on the component side or on the back of the printed circuit board.
DE 43 32 115 B4 discloses a printed circuit board cooling arrangement using a heat sink disposed on the component side. An electrically insulating but thermally conducting adhesive foil connects the heat sink to the conductor tracks leading to the SMD component. However, the thermally conductive adhesive foil itself possesses a thermal resistance. The application of the adhesive foil requires an additional manufacturing step. The cooling fins are perpendicular to the plane of the component side of the printed circuit board. For natural convection, cooling is therefore dependent on the position in space of the printed circuit board.
An electrical device comprising a printed circuit board on which the SMD components are cooled by a heat sink on the underside of the printed circuit board is disclosed in DE 199 10 500 A1. By means of thermal vias, the heat dissipated on the component side is conducted to the back of the printed circuit board. The provision of thermal vias likewise constitutes an increased printed circuit board manufacturing cost.
These known heat removal concepts are costly in manufacturing terms and also have the disadvantage that heat dissipation by natural convection is dependent on the mounting position. Under worst case conditions a hot spot may occur which can impair the operational capability of the SMD circuit.